Between 1982 and 1988 the NHLBI, the NIAID, and the Clinical Center conducted a prospective randomized trial of anti-inflammatory therapy in idiopathic dilated, after 6 to 9 years of followup, 67 of the 123 patients had died and another 23 had undergone cardiac transplantation. Of the remaining 33 non-transplanted survivors, almost half were asymptomatic. This protocol (93-CC-0096)involves non-invasive followup re-evaluation of these 33 patients, including radionuclide cineangiography, echocardiography, Holter monitoring, and exercise testing. During FY1994, the status of all 33 patients was reconfirmed by mail and telephone surveys. Travel funds became available, and the first 3 patients underwent inpatient study at the Clinical Center. When completed, this study will represent the first prospective description of the long-term natural history of idiopathic dilated cardiomyopathy in a well-characterized cohort of referral patients. Objective data concerning cardiac size and cardiac function among long- term survivors will permit clinicians to advise newly diagnosed dilated cardiomyopathy patients regarding their prospects for long-term remission.